though not sure (me uses spdif) i think 8 channel means 8 channels aes/ebu in both directions, therefore it shouldn´t be a problem to connect 2xAD and 8xDA converter channels. but as tiny supposes, check if this relates to the highest sample rates (dirty little marketing tricks etc.) the converter x may offer. just ask the manufacturers of the products you´re aiming at for total clearance.
So does it mean that a Lynx Aurora 8 can also handle them as it has also 8 AES/EBU I/O ?
Yes, the Lynx Aurora 8 does offer 8 AES I/O. You can use the Lynx CBL-DIGY85 to interconnect the Digi 192's XLR AES I/O. OR, just get the LT-HD card for the Aurora, and directly interface the Lynx AD/DA, as well as the AES I/O, with PTHD, which would give you 8 AD/DA and 8 AES I/O.